Dispersant viscosity modifiers with amine functionality

ABSTRACT

A lubricating composition includes an oil of lubricating viscosity and an oil-soluble dispersant viscosity modifier. The dispersant viscosity modifier includes an olefin-based polymer backbone and at least one pendent group derived from a functionalized aliphatic amine. Each pendent group is independently attached to the olefin-based polymer backbone. The pendent group is non-ionic, non-basic, and non-acidic and includes a functional group which includes at least one heteroatom other than nitrogen.

This application is a Continuation of U.S. application Ser. No.15/508,692, filed Mar. 3, 2017, and claims the priority of InternationalApplication PCT/US2015/050157, filed Sep. 15, 2015, and U.S. ProvisionalApplication Ser. No. 62/050,325, filed Sep. 15, 2014, from which the PCTapplication claims priority, the disclosures of which are incorporatedherein by reference, in their entireties.

BACKGROUND

Aspects of the exemplary embodiment relate to a dispersant viscositymodifier, and more specifically to a dispersant viscosity modifier withan amine functionality and to a lubricating composition, such as anengine oil, which includes the described dispersant viscosity modifier.Aspects of the exemplary embodiment also relate to a method for use ofthe described dispersant viscosity modifier to improve the filmthickness and/or antiwear performance of such a lubricating composition.

Lubricating oil compositions desirably maintain a relatively stableviscosity over a wide range of temperatures. Viscosity modifiers areoften used to reduce the extent of the decrease in viscosity as thetemperature is raised or to reduce the extent of the increase inviscosity as the temperature is lowered, or both. Thus, a viscositymodifier ameliorates the change of viscosity of an oil containing itwith changes in temperature. The fluidity characteristics of the oil arethereby improved.

Traditional dispersant viscosity modifiers (DVMs) made fromethylene-propylene copolymers that have been grafted with maleicanhydride and reacted with various amines have shown desirableperformance to prevent oil thickening in diesel engines. However, thesematerials can sometimes provide poor antiwear protection, especially inhigh soot conditions, leading to increased wear, particularly of seals,for example on the valve train and/or various parts of the crankcase,and expose the components to corrosion.

There is an ongoing need for dispersant viscosity modifiers that provideviscosity control but which also provide good wear protection andcorrosion resistance.

U.S. Pub. No. 2013/0303418, published Nov. 14, 2013, entitled HIGHMOLECULAR WEIGHT POLYMERS AS VISCOSITY MODIFIERS, by FALENDER, et al.,discloses a lubricating composition which comprises a base oil andbetween 10 ppm and 1000 ppm by mass of a viscosity modifier, theviscosity modifier comprising an olefin copolymer. The use of additionalmonomers is anticipated to allow the inventive polymer to have theproperties of dispersants, antioxidants, pour point depressants andother additive chemistry.

U.S. Pat. No. 4,632,769, issued Dec. 30, 1986, entitled ETHYLENECOPOLYMER VISCOSITY INDEX IMPROVER-DISPERSANT ADDITIVE USEFUL IN OILCOMPOSITIONS, by Gutierrez, et al. describes oil soluble viscosity indeximproving ethylene copolymers, such as copolymers of ethylene andpropylene, which are reacted or grafted with ethylenically unsaturatedcarboxylic acid moieties and reacted with polyamines having two or moreprimary amine groups.

U.S. Pat. No. 5,433,757, issued Jul. 18, 1995, entitled ETHYLENEALPHA-OLEFIN POLYMER SUBSTITUTED MONO- AND DICARBOXYLIC ACID DISPERSANTADDITIVES, by Song, et al., discloses an oil-soluble fuel andlubricating oil additive comprising at least one terminally unsaturatedethylene alpha-olefin polymer of 300 to 20,000 number average molecularweight substituted with mono- or dicarboxylic acid producing moietiesand can also be reacted with a nucleophilic reagent, such as amines,alcohols, amino alcohols and reactive metal compounds, to form productswhich are also useful fuel and lubricating oil additives.

U.S. Pat. No. 4,632,769, issued Dec. 30, 1986, entitled ETHYLENECOPOLYMER VISCOSITY INDEX IMPROVER-DISPERSANT ADDITIVE USEFUL IN OILCOMPOSITIONS, by Gutierrez, et al. describes oil soluble viscosity indeximproving ethylene copolymers, which are reacted or grafted withethylenically unsaturated carboxylic acid moieties and reacted withpolyamines having two or more primary amine groups and a C22 to C28olefin carboxylic acid component.

U.S. Pat. No. 4,137,185, issued Jan. 30, 1979, entitled STABILIZED IMIDEGRAFT OF ETHYLENE COPOLYMERIC ADDITIVES FOR LUBRICANTS, by Gardiner, etal., discloses reacting C1 to C30 monocarboxylic acid anhydrides, anddicarboxylic anhydrides, such as acetic anhydride, succinic anhydride,etc. with an ethylene copolymer reacted with maleic anhydride and apolyalkylene polyamine to inhibit cross linking and viscosity increasedue to further reaction of any primary amine groups which were initiallyunreacted.

PCT Pub. WO 2011/146692, published Nov. 24, 2011, discloses alubricating composition containing a copolymer including units derivedfrom an α-olefin and an ethylenically unsaturated carboxylic acid orderivatives thereof, esterified and amidated with an alcohol and anaromatic amine.

US Pub. No. 20140051615, published Feb. 20, 2014, entitledFUNCTIONALIZED COPOLYMERS AND LUBRICATING COMPOSITIONS THEREOF, bySalomon, et al., discloses a lubricating composition containing an oilof lubricating viscosity and a dimercaptothiadiazole salt of a copolymercomprising units derived from an α-olefin and an ethylenicallyunsaturated carboxylic acid or derivatives thereof (typically carboxylicacid groups or an anhydride), which are partially esterified with analcohol. A portion of carboxylic acid groups not esterified are reactedwith an amine.

WO 2014/047017, published Mar. 27, 2014, to The Lubrizol Corp., entitledLUBRICANT COMPRISING A MIXTURE OF AN OLEFIN-ESTER COPOLYMER WITH ANETHYLENE ALPHA-OLEFIN COPOLYMER, discloses a lubricant compositioncontaining an oil of lubricating viscosity and an esterified copolymerwith a backbone containing units derived from an alpha-olefin monomer ofat least 6 carbon atoms and an ethylenically unsaturated carboxylic acidor derivative thereof, optionally containing nitrogen functionality; andan ethylene alpha-olefin copolymer comprising greater than 5 weightpercent ethylene monomer units. The nitrogen functionality may bederived from reaction with an amine, such as morpholines,imidazolinones, aminoamides, β-alanine alkyl esters, aliphatic amines,aromatic amines, aliphatic polyamines, and aromatic polyamines.

U.S. Provisional Application 61/704,734, filed September 2012, and PCTApplication 2012/060025 (WO2014047017), filed September 2013, entitledMIXTURES OF OLEFIN-ESTER COPOLYMER WITH ETHYLENE α-OLEFIN COPOLYMER ASVISCOSITY MODIFIER, disclose a lubricant composition including an oil oflubricating viscosity and an esterified copolymer with a backbonecomprising units derived from an α-olefin monomer and an ethylenicallyunsaturated carboxylic acid. The copolymer may include nitrogenfunctionality derived from reaction with an amine selected frommorpholines, imidazolinones, aminoamides, α-alanine alkyl esters,aliphatic amines, aromatic amines, aliphatic polyamines, and aromaticpolyamines, and mixtures thereof.

BRIEF DESCRIPTION

In accordance with one aspect of the exemplary embodiment, a lubricatingcomposition includes an oil of lubricating viscosity and an oil-solubledispersant viscosity modifier. The dispersant viscosity modifierincludes an olefin-based polymer backbone and at least one pendent groupderived from a functionalized aliphatic amine. Each of the at least onependent groups is independently attached to the olefin-based polymerbackbone and is non-ionic, non-basic, and non-acidic and includes afunctional group comprising at least one heteroatom other than nitrogen.

In accordance with another aspect of the exemplary embodiment, a processfor making a lubricating composition includes providing an olefin-basedpolymer backbone comprising acylating groups and reacting at least oneof the acylating groups with a functionalized aliphatic amine to provideat least one pendent group. Each pendent group is independently attachedto the olefin-based polymer backbone and is non-ionic, non-basic, andnon-acidic and includes a functional group comprising at least oneheteroatom other than nitrogen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a Stribeck plot of traction coefficient vs. log mean speed(mm/s) for lubricating compositions formed with and without an aminateddispersion viscosity modifier; and

FIG. 2 is a plot of Central Film Thickness (nm) vs. speed (m/s) forlubricating compositions formed with and without an aminated dispersionviscosity modifier.

DETAILED DESCRIPTION

The exemplary embodiment relates to a lubricating composition whichincludes an oil of lubricating viscosity and a dispersant viscositymodifier that includes an olefin-based polymer with pendent groupsderived from a functionalized aliphatic amine.

The exemplary dispersant viscosity modifier has improved performance inengine tests, providing a good viscosity index, good soot dispersionand/or toleration properties, while also providing good antiwearprotection and/or corrosion resistance.

The exemplary lubricating composition finds particular application as anengine oil for passenger vehicles and heavy duty diesel vehicles.

The amounts of additives present in the lubricating compositiondisclosed herein are expressed on an oil free basis, i.e., amount ofactives, unless otherwise noted.

The Dispersant Viscosity Modifier

The exemplary aminated dispersant viscosity modifier is a material thatprovides viscosity modifier performance in a lubricating compositionwhile also providing dispersant functionality. The aminated dispersantviscosity modifier enables the lubricating composition to provide atleast one of antiwear performance, friction modification (particularlyfor enhancing fuel economy), extreme pressure performance, antioxidantperformance, lead, tin or copper (typically lead) corrosion inhibition,decreased corrosiveness towards acrylate or fluoroelastomer seals, orseal swell performance. In particular, reduced corrosion and sealsdegradation may be obtained. The dispersant viscosity modifier mayprovide additional and or other benefits to a lubricating composition.

By “oil soluble,” it is meant that the dispersion viscosity modifier issoluble in oil at least to the amounts described herein for desirablefor serving its intended purpose.

The exemplary dispersant viscosity modifier is an oil-soluble polymer,which includes a polymer backbone, such as an olefin-based polymer, andone or more pendent groups each independently attached to theolefin-based polymer. The pendent groups are derived from afunctionalized aliphatic amine.

Each of the pendent groups is attached to the polymer chain by asuccinimide linkage through a linking unit derived from an ethylenicallyunsaturated carboxylic acid monomer or derivative thereof. These linkingunits may be grafted onto the olefin-based polymer or form a part of thepolymer backbone. The linking group thus links the pendent group to theolefin-based polymer. Each linking group may be derived from adicarboxylic acid, such as maleic anhydride.

The aminated dispersant viscosity modifier can be represented by amolecule of the general formula (I):

P—(X—Y)_(x)  (I),

where P represents the olefin-based polymer, X represents the linkinggroup, Y represents the pendent group derived from the functionalizedaliphatic amine, and x is at least 1, such as from 1 to 20, or 1 to 10,or 1 to 8, e.g., at least 2. As it will be appreciated, there may bemany molecules of Formula (I) in the lubricating composition, so thevalues of x may be considered number average values over all themolecules present. A ratio by weight of linking groups X to the polymerbackbone P in the dispersant viscosity modifier may be at least 1:100,or at least 2:100, such as at least 3:100, and in some embodiments, isup to up to 20:100 or up to 10:100.

In some embodiments, P is an ethylene-olefin-based copolymer and theviscosity modifier of Formula (I) is represented by Formula (II) or(III):

—[[(CH₂)_(m)—CHR—CH₂]_(n-p)—[(CH₂)_(m)—CR(X—Y)—CH₂]_(p)]_(q)—  (II)

—[[(CH₂)_(m)—CHR—CH₂]_(n)—[X(Y)]_(p)]_(q)—  (III)

where each R represents H or an alkyl group containing from 1 to 8carbon atoms,

m, n, and p are independently at least 1,

q is at least 1, such as at least 2.

Formula (II) represents a viscosity modifier in which the linking groupX is grafted onto the polymer backbone P, which can be of the generalform [(CH₂)_(m)—CHR—CH₂]_(n) prior to grafting. Formula (III) representsa viscosity modifier in which the linking group X is integral with thepolymer backbone P.

As will be appreciated, fewer than all of the linking groups X may belinked to a pendent group Y, although in one embodiment, a majority (atleast 50%), or substantially all (at least 80%, or at least 90%, or atleast 95%), or all of the linking groups X are linked to a respectivependent group Y.

In some embodiments, a ratio of n:p (number ethylene olefin units:numberof pendent groups Y) in the molecules of Formulas (II) and (III) (e.g.,averaged over all molecules) is at least 2:1, or at least 5:1, or atleast 10:1, and in some embodiments, is up to 10,000:1, or up to 1000:1,or up to 100:1.

The functionalized aliphatic amine includes a primary amino groupcapable of reacting with the linking units derived from theethylenically unsaturated carboxylic acid or derivative thereof of thebackbone to form a succinimide.

Each pendent group Y derived from the functionalized aliphatic amine isnon-ionic, non-basic, and non-acidic.

By “aliphatic” it is meant that the functionalized aliphatic amine, andthe pendent group Y derived therefrom, has no aromatic groups as part ofthe functionalized aliphatic amine or pendent group or which are linkeddirectly or indirectly to the pendent group.

By “non-ionic” it is meant that the bonds within the pendent group areall covalent.

By “non-basic” it is meant that the pendent groups themselves havesubstantially no basic character, resulting in a dispersant viscositymodifier having a low total base number (TBN). TBN is a measure of alubricant's reserve alkalinity. It is measured in milligrams ofpotassium hydroxide per gram (mg KOH/g). TBN is determined according tothe method described in ASTM D2896-11, “Standard Test Method for BaseNumber of Petroleum Products by Potentiometric Perchloric AcidTitration,” ASTM International, West Conshohocken, Pa., 2003, DOI:10.1520/D2896-11. The TBN of the dispersant viscosity modifier, on anoil-free basis, may be less than 5, or less than 3. In theory, the TBNmay be at or very close to zero when there are no basic nitrogen atomsremaining after reaction of the amine head group with the polymerbackbone. However, because of the possibility for some unreacted aminein the mixture, the dispersant viscosity modifier composition may have aslight basic character. The TBN of the final lubricating composition canbe adjusted, using other additives, to a desired level for optimumperformance. In other embodiments, the dispersant viscosity modifier mayhave a higher TBN, such as over 10, e.g., up to 20, or up to 15, on anoil-free basis, such as when there is a basic nitrogen atom remainingafter reaction of the amine head group with the polymer backbone.However, a dispersant viscosity modifier with a low TBN is particularlyeffective.

By “non-acidic” it is meant that the pendent groups themselves havesubstantially no acidic character, i.e., substantially no acidicprotons, resulting in a dispersant viscosity modifier having a low totalacid number (TAN), by which it is meant a TAN of less than 10, or lessthan 5, or less than 3, or less than 1, on an oil free basis. TAN isdetermined according to the method described in ASTM D664-11A, “StandardTest Method for Acid Number of Petroleum Products by PotentiometricTitration,” ASTM International, West Conshohocken, Pa., 2003 DOI:10.1520/D0664-11A. In other embodiments, the dispersant viscositymodifier may have a higher TAN, such as over 15, e.g., up to 25, or upto 20, on an oil-free basis, such as when there is an acidic carboxylicacid group remaining after reaction of the amine head group with thepolymer backbone. However, a dispersant viscosity modifier with a lowTAN is particularly effective.

The functionalized aliphatic amine and the pendent group Y derivedtherefrom include at least one functional group which includes at leastone heteroatom other than nitrogen. Such heteroatoms include oxygen andsulfur. In one embodiment the functional group includes oxygen as theheteroatom. Suitable functional groups that include oxygen includehydroxyl, ester, ether, urea and amide functional groups. In theexemplary embodiment, the functional group is a terminal group and isnot further reacted so that it remains available in the lubricatingcomposition to help to provide the useful properties of the dispersionviscosity modifier.

In an exemplary embodiment, the functionalized aliphatic amine is amonoamine, i.e., has only one amino group. In one embodiment, anynitrogens in the functionalized aliphatic amine that are not part of theamino group are not ionized (do not have a counterion), i.e., are threecoordinate. The pendent groups, and the dispersion viscosity modifier asa whole, can thus be free of quaternary ammonium ions (NH₄ ⁺) andsimilarly free of quaternary phosphonium ions.

The functional group may be spaced from a nitrogen derived from thefunctionalized aliphatic amine by a C₄-C₂₄ hydrocarbyl group.

Exemplary hydroxyl alkyl amines useful for forming pendent group Yinclude those which have at least one hydroxyl group (—OH), such as aprimary hydroxyl group (—CH₂—OH) or secondary hydroxyl group (>CH—OH),and at least one primary amino group (—NH₂).

Suitable alkanolamines are those having the formula:

where R¹ is an alkyl group having from 1 to 20 or 1 to 10 carbon atoms,which forms an alcohol functionalized succinimide on reaction with theunits derived from the ethylenically unsaturated carboxylic acid orderivative thereof of the backbone.

Examples of such alkanolamines include ethanolamine, 3-aminopropan-1-ol,4-aminobutan-1-ol, 5-aminopentan-1-ol, 6-aminohexan-1-ol,7-aminoheptan-1-ol, 8-aminooctan-1-ol, 2-(2-aminoethylamino)ethanol,3-amino-2,2-dimethylpropan-1-ol, 2-(2-aminoethoxy)ethanol,N-(2-hydroxyethyl)- and 1,3-propanediamine.

In one embodiment, the hydroxyl alkyl amine is a monoamine.

In some embodiments the hydroxyl alkyl amine is a secondary amine, suchas 2-aminopropan-1-ol, 2-aminobutan-1-ol, 3-aminobutan-1-ol,2-aminopentan-1-ol, 2-aminohexan-1ol, 2-aminoheptan-1-ol, or2-aminooctan-1-ol.

Exemplary aminoalkyl esters useful for forming pendent group Y includethose which have at least one carboxyl group (R—COO), and at least oneprimary amino group (—NH₂).

Suitable aminoalkyl esters are those having the formula:

where R² is an alkyl group having from 1 to 20 or 1 to 10 carbon atomsand R³ is an alkylene group having 1 to 20 or 1 to 10 carbon atoms,which forms an unsaturated ester-functional succinimide on reaction withthe units derived from the ethylenically unsaturated carboxylic acid orderivative thereof of the backbone.

Examples of aminoalkyl esters useful for forming pendent group Y includemethyl 2-aminoacetate, ethyl 2-aminoacetate, propyl 2-aminoacetate,butyl 2-aminoacetate, methyl 3-aminopropionate, 3-ethoxypropylamine,3-propoxypropylamine, 3-butoxypropylamine, methyl 4-aminobutanoate,4-ethoxybutylamine, 4-propoxybutylamine, 4-butoxybutylamine, methyl5-aminopentanoate, ethyl 5-aminopentanoate, propyl 5-aminopentanoate,butyl 5-aminopentanoate, methyl 6-aminohexanoate, ethyl6-aminohexanoate, propyl 6-aminohexanoate, and butyl 6-aminopropionate.

Exemplary aminoalkyl ethers useful for forming pendent group Y includethose which have at least one carbonyl group (R—CO—), and at least oneprimary amino group (—NH₂).

Suitable aminoalkyl ethers are those having the formula:

where R⁴ is an alkyl group having from 1 to 20 or 1 to 10 carbon atomsand R⁵ is an alkylene group having 1 to 20 or 1 to 10 carbon atoms,which forms an unsaturated ether-functional succinimide on reaction withthe units derived from the ethylenically unsaturated carboxylic acid orderivative thereof of the backbone.

Examples of aminoalkyl ethers include 2-methoxyethylamine,2-ethoxyethylamine, 2-propoxyethylamine, and 2-butoxyethylamine.

Suitable aminoalkyl ureas useful for forming pendent group Y are thosehaving the formula:

where R⁶ is an alkylene group having from 1 to 20 or 1 to 10 carbonatoms and R⁷ is an alkylene group having 1 to 20 or 1 to 10 carbonatoms, which forms an unsaturated urea-functional succinimide onreaction with the units derived from the ethylenically unsaturatedcarboxylic acid or derivative thereof of the backbone.

Examples of aminoalkyl ureas include aminoethyl ethylene urea,aminoethyl propylene urea, aminopropyl ethylene urea, and aminopropylpropylene urea.

Suitable aminoalkyl amides are those having the formula:

where R⁸ and R⁹ are independently H or an alkyl group having from 1 to20 or 1 to 10 carbon atoms and R¹⁰ is an alkylene group having 1 to 20or 1 to 10 carbon atoms, which forms an unsaturated amide-functionalsuccinimide on reaction with the units derived from the ethylenicallyunsaturated carboxylic acid or derivative thereof of the backbone. Inone embodiment, at least one of R⁸ and R⁹ is H.

In some embodiments, the aminated dispersant viscosity modifier includesfrom 1 to 50 of the described pendent group Y, or from 1 to 30, or from1 to 20, or 1 to 10, or from 1 to 6, or 1 to 4, per molecule of thedispersant viscosity modifier, on average. In some embodiments, theaminated dispersant viscosity modifier includes 1, 2, 3, 4, 5 or 6pendent group Y, on average.

The exemplary linking groups X are acylating groups, each independentlyattached or part of the polymer's backbone. The linking group X may bederived from an ethylenically unsaturated carboxylic acid monomer, suchas a dicarboxylic acid, or functional equivalent thereof, or a polyol.In some embodiments, the linking group X is derived from maleicanhydride. In some embodiments, the unsaturated carboxylic reactant isgrafted on to the olefin-based polymer backbone and the functionalizedaliphatic amine is reacted with the unsaturated carboxylic reactantgroup containing olefin-based polymer backbone. In other embodiments,the unsaturated carboxylic reactant is present in the olefin-basedpolymer backbone and the functionalized aliphatic amine is reacted withthe unsaturated carboxylic reactant group containing olefin-basedpolymer backbone.

The polymer backbone P employed in the aminated dispersant viscositymodifier is not particularly limited, provided that it can be modifiedwith a carboxylic acid functionality or a reactive equivalent of thecarboxylic acid functionality (e.g., anhydride or ester) that serves asthe linking group described above.

Suitable olefin-based polymer backbones P include ethylene, propylene,and butylene polymers, copolymers thereof, copolymers thereof furthercontaining a non-conjugated diene, and isobutylene/conjugated dienecopolymers, each of which can be subsequently supplied with graftedcarboxylic functionality to serve as the linking group or havecarboxylic functionality in the backbone itself (such as anethylene-propylene-co-maleimide). In some embodiments, the polymerbackbone P is an ethylene-olefin-based polymer, such as an ethylenepropylene copolymer. In some embodiments, the olefin-based polymer is acopolymer where ethylene makes up at least 10% of the monomer used toprepare the copolymer on a molar basis, or at least 20 mole %, or atleast 50 mole %.

Ethylene-propylene or higher alpha monoolefin copolymers may consist of15 to 80 mole % ethylene and 20 to 85 mole % propylene or highermonoolefin. In some embodiments, the mole ratio is 30 to 80 mole %ethylene and 20 to 70 mole % of at least one C₃ to C₁₀ alpha monoolefin,for example, 50 to 80 mole % ethylene and 20 to 50 mole % propylene.Terpolymer variations of the foregoing polymers may contain up to 15mole % of a non-conjugated diene or triene.

In these embodiments, the polymer backbone (e.g., the ethylene copolymeror terpolymer), can be an oil-soluble, substantially linear, rubberymaterial. Also, in certain embodiments, the polymer can be in formsother than substantially linear, that is, it can be a branched polymeror a star polymer. The polymer can also be a random copolymer or a blockcopolymer, including di-blocks and higher blocks, including taperedblocks and a variety of other structures.

The polymer backbone (olefin-based polymer) may have a number averagemolecular weight Mn (measured by gel permeation chromatography, using apolystyrene standard), which can be up to 150,000 or higher, e.g., atleast 1,000 or at least 3,000 or at least 5,000, such as up to 150,000or up to 120,000, or up to 100,000, or up to 50,000, or up to 15,000,e.g., about 3,000 to about 15,000. The aminated dispersant viscositymodifier may have a number average molecular weight Mn (by gelpermeation chromatography, polystyrene standard), which can be up to150,000 or higher, e.g., at least 2,000 or at least 3,000 or at least5,000, such as up to 150,000 or up to 120,000, or up to 100,000, or upto 50,000, or up to 18,000, e.g., about 4,000 to about 16,000.

The term “polymer” is used generically to encompass homopolymers, suchas ethylene or higher alpha monoolefin polymers, copolymers, terpolymersand/or interpolymers. These materials may contain minor amounts of otherolefinic monomers so long as their basic characteristics are notmaterially changed.

In one embodiment, the exemplary aminated dispersant viscosity modifieris formed by reacting a carboxylic acid-modified polymer backbone with afunctionalized aliphatic amine. The unsaturated carboxylic acid monomerused to form the linking group X may be derived from maleic acid and/oranhydride. As noted above, this portion of the linking group may beincorporated and/or attached to the polymer backbone during thepolymerization of the polymer backbone, for example, by mixing a monomercontaining the linking group in with the other monomers used to preparethe polymer backbone. In other embodiments, this part of the linkinggroup may be added by grafting the group onto an already preparedpolymer backbone.

As noted above, in some embodiments the unsaturated carboxylic acid usedto form the linking group is contained within a monomer copolymerizedwithin the polymer backbone chain. In other embodiments, the unsaturatedcarboxylic reactant may be present as a pendent group attached by, forexample, a grafting process.

Examples of suitable carboxylic-acid containing polymers, which arerepresentative of the polymer backbone described above with carboxylicreactant portion of the liking group attached, include maleicanhydride-ethylene-propylene copolymers, maleic anhydride-styrenecopolymers, including partially esterified versions thereof, andcopolymers thereof. Nitrogen-containing esterified carboxyl-containinginterpolymers prepared from maleic anhydride and styrene-containingpolymers are described in U.S. Pat. No. 6,544,935 to Vargo, et al. Otherpolymer backbones which are used for preparing dispersants may also beused. For example, polymers derived from isobutylene and isoprene aredescribed in U.S. Pub. No. 20040034175 to Kolp. Other suitable polymerbackbones include substantially hydrogenated copolymers of vinylaromatic materials such as styrene and unsaturated hydrocarbons such asconjugated dienes, e.g., butadiene or isoprene. In substantiallyhydrogenated polymers of this type, the olefinic unsaturation istypically substantially completely hydrogenated by known methods, butthe aromatic unsaturation may remain. Such polymers can include randomcopolymers, block copolymers, or star copolymers. Yet other suitablebackbone polymers include styrene-ethylene-alpha olefin polymers, asdescribed in PCT publication WO 2001/030947, and polyacrylates orpolymethacrylates. In the case of such poly(meth)acrylates, the(meth)acrylate monomers within the polymer chain itself may serve as thecarboxylic acid functionality or reactive equivalent thereof which isused to react with the amine functionality which provides the linkerunit X. Alternatively, additional acid functionality may becopolymerized into the (meth)acrylate chain or even grafted onto it,particularly in the case of acrylate polymers.

In certain embodiments, the polymer backbone may be prepared fromethylene and propylene or it may be prepared from ethylene and a higherolefin within the range of (C₃ to C₁₀) alpha-monoolefins, which may thenin either case be grafted with a suitable carboxylic acid-containingmonomer, to serve as the linking group X.

More complex polymer backbones, often designated as interpolymers, mayalso be included. Such materials are generally used to prepare aninterpolymer backbone is a polyene monomer selected from conjugated ornon-conjugated dienes and trienes. The non-conjugated diene component isone having from about 5 to about 14 carbon atoms. In one embodiment, thediene monomer is characterized by the presence of a vinyl group in itsstructure and can include monocyclic and bicyclic compounds.Representative dienes include 1,4-hexadiene, 1,4-cyclohexadiene,dicyclopentadiene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene,1,5-heptadiene, and 1,6-octadiene. A mixture of more than one diene canbe used in the preparation of the interpolymer.

The ethylenically unsaturated carboxylic acid monomer may be graftedonto the polymer backbone in a number of ways, such that a resultingpolymer intermediate with linking groups X is characterized by havingcarboxylic acid acylating functions within its structure. Such materialswhich are attached to the polymer typically contain at least oneethylenic bond (prior to reaction) and at least one, or at least two,carboxylic acid (or its anhydride) groups or a polar group which isconvertible into the carboxyl groups by oxidation or hydrolysis. Maleicanhydride or an alkyl-substituted derivative thereof (e.g., methylmaleic anhydride or ethyl maleic anhydride) is suitable for forming thelinking groups. It grafts onto the ethylene copolymer or terpolymer togive two carboxylic acid functionalities. Examples of additionalunsaturated carboxylic materials include chlormaleic anhydride, itaconicanhydride, and the corresponding dicarboxylic acids, such as maleicacid, fumaric acid, acrylic acid, cinnamic acid, and their esters.

Example intermediate polymers of this type are available from Mitsuiunder the tradename Lucant™, such as Lucant™ A-5320H polymer. LucantA-5320H is an amorphous Ziegler-Natta copolymer of ethylene andpropylene (GPC M_(n)=7700) that is randomly grafted with maleicanhydride (in the presence of a free radical peroxide initiator in ahigh shear mixer) to a level of about 3.5 weight % maleic anhydride. Thefinal product has molecular weight (GPC polystyrene standards)M_(n)=8810 and M_(w)=17200 and a Total Acid Number of 40 to 45 mg KOH/g.

The polymer intermediate may then be reacted with the functionalizedaliphatic amine to provide the dispersant viscosity modifier. In otherembodiments, the pendent groups may be functionalized after reaction ofan amine with the linking group.

The reaction can be carried out in a suitable vehicle, such as a diluentoil and/or toluene, at a sufficient temperature, such as at least 90° C.or at least 100° C., but below the decomposition temperature of theproduct.

The aminated dispersant viscosity modifier may be present in thelubricating composition at a concentration of at least 0.05 weight %,such as at least 0.1 weight %, or at least 0.2 weight %, or at least 0.5weight %. The aminated dispersant viscosity modifier may be present inthe lubricating composition at a concentration of up to 10 weight %,such as up to 5 weight %, or up to 3 weight %, or up to 2.3 weight %.

HLB values reported herein are determined by the Griffin Method (seeGriffin, William C. (1949), “Classification of Surface-Active Agents by‘HLB’”, Journal of the Society of Cosmetic Chemists 1 (5): 311-26 andGriffin, William C. (1954), “Calculation of HLB Values of Non-IonicSurfactants”, Journal of the Society of Cosmetic Chemists 5 (4): 249-56

In Griffin's method, HLB=20*Mh/M, where Mh is the molecular mass of thehydrophilic portion of the molecule and M is the molecular mass of thewhole molecule. This method covers a range from 0-20.

The exemplary aminated dispersant viscosity modifier may have an HLBvalue according to the Griffin method, of at least 2, or at least 2.5,or at least 3, and can be up to 4.5 or up to 4 for polymer backbonesprepared with an average of 3.5 maleic anhydride groups per chain. Forpolymer backbones prepared with greater amounts of maleic anhydridegrafted onto them, such as 6.2 groups per chain, the HLB range can be upto about 6.0.

For example, a dispersant viscosity modifier with an ethylene propylenebackbone having about 240 CH₂/CH/CH₃ groups has a molecular mass ofapproximately 3525, as determined by vapor phase osmometry (VPO). Whenreacted with 3.5 wt % maleic anhydride (e.g., forming Lucant A-5320H),each polymer backbone chain has, on average, 3.5 sites which can befunctionalized with the functionalized aliphatic amine. When reactedwith 3-aminopropanol or aminoethyl ethylene urea for example thisprovides a head group of the form:

Considering these entire head group portions as the respectivehydrophilic portion, the Mh term is approximately 156.2*3.5=547 for theaminopropanol-based head group. Therefore, the HLB=20*547/(3525+547)=2.7for a dispersant viscosity modifier composed of an ethylenepropylenecopolymer aminopropanol pendent groups.

In a similar fashion, the HLB for the dispersant viscosity modifiercomposed of an ethylenepropylene copolymer with aminoethyl ethylene ureapendent groups can be computed as 3.5.

Under the method described herein, the entire head group is consideredas the hydrophilic portion, even though it contains some hydrocarbonportions.

Oils of Lubricating Viscosity

The exemplary lubricating composition includes an oil of lubricatingviscosity. Suitable oils include both natural and synthetic oils, oilderived from hydrocracking, hydrogenation, and hydrofinishing,unrefined, refined, re-refined oils or mixtures thereof.

Unrefined oils are those obtained directly from a natural or syntheticsource generally without (or with little) further purificationtreatment.

Refined oils are similar to the unrefined oils except they have beenfurther treated in one or more purification steps to improve one or moreproperties. Purification techniques are known in the art and includesolvent extraction, secondary distillation, acid or base extraction,filtration, percolation and the like.

Re-refined oils are also known as reclaimed or reprocessed oils, and areobtained by processes similar to those used to obtain refined oils andoften are additionally processed by techniques directed to removal ofspent additives and oil breakdown products.

Natural oils useful in making the inventive lubricants include animaloils, vegetable oils (e.g., castor oil), mineral lubricating oils suchas liquid petroleum oils and solvent-treated or acid-treated minerallubricating oils of the paraffinic, naphthenic or mixedparaffinic-naphthenic types and oils derived from coal or shale ormixtures thereof.

Synthetic lubricating oils are useful and include hydrocarbon oils suchas polymerized, oligomerized, or interpolymerized olefins (e.g.,polybutylenes, polypropylenes, propyleneisobutylene copolymers);poly(1-hexenes), poly(1-octenes), trimers or oligomers of 1-decene,e.g., poly(1-decenes), such materials being often referred to as polyα-olefins, and mixtures thereof; alkyl-benzenes (e.g., dodecylbenzenes,tetradecylbenzenes, dinonylbenzenes, di-(2-ethylhexyl)-benzenes);polyphenyls (e.g., biphenyls, terphenyls, alkylated polyphenyls);diphenyl alkanes, alkylated diphenyl alkanes, alkylated diphenyl ethersand alkylated diphenyl sulfides and the derivatives, analogs andhomologs thereof or mixtures thereof.

Other synthetic lubricating oils include polyol esters (such asPriolube®3970), diesters, liquid esters of phosphorus-containing acids(e.g., tricresyl phosphate, trioctyl phosphate, and the diethyl ester ofdecane phosphonic acid), or polymeric tetrahydrofurans. Synthetic oilsmay be produced by Fischer-Tropsch reactions and typically may behydroisomerized Fischer-Tropsch hydrocarbons or waxes. In oneembodiment, oils may be prepared by a Fischer-Tropsch gas-to-liquidsynthetic procedure as well as other gas-to-liquid oils.

The base oil may be selected from any of the base oils in Groups I-V ofthe American Petroleum Institute (API) Base Oil InterchangeabilityGuidelines, namely

Base Oil Category Sulfur (%) Saturates(%) Viscosity Index Group I >0.03and/or <90 80 to 120 Group II ≤0.03 and ≥90 80 to 120 Group III ≤0.03and ≥90 >120 Group IV All polyalphaolefins (PAOs) Group V All others notincluded in Groups I, II, III or IV

Groups I, II and III are mineral oil base stocks. Oils of lubricatingviscosity may also be defined as specified in April 2008 version of“Appendix E—API Base Oil Interchangeability Guidelines for Passenger CarMotor Oils and Diesel Engine Oils”, section 1.3 Sub-heading 1.3. “BaseStock Categories.” In one embodiment, the oil of lubricating viscositymay be an API Group II or Group III oil. In one embodiment, the oil oflubricating viscosity may be an API Group I oil.

The oil of lubricating viscosity may have a kinematic viscosity of lessthan 15 mm²/s (cSt) at 100° C., and in other embodiments 1-12 or 2-10 or3-8 or 4-6 mm²/s. Kinematic viscosity is determined by ASTM D445-12,“Standard Test Method for Kinematic Viscosity of Transparent and OpaqueLiquids (and Calculation of Dynamic Viscosity)”, ASTM International,West Conshohocken, Pa., DOI: 10.1520/D0445-12. The dispersant viscositymodifier may have a kinematic viscosity at 100° C. of at least 35 mm²/s,or at least 100 mm²/s, or at least 500 mm²/s.

The amount of the oil of lubricating viscosity present is typically thebalance remaining after subtracting from 100 wt % the sum of the amountof the aminated dispersant viscosity modifier and the other performanceadditives. The oil of lubricating viscosity may be present in thelubricating composition at a concentration of at least 10 wt %, or atleast 20 wt %, or at least 40 wt %, or at least 80 wt %, and may be upto 99 wt %, or up to 95 wt %, or up to 90 wt %.

The lubricating composition may be in the form of a concentrate and/or afully formulated lubricant. If the lubricating composition (comprisingthe additives disclosed herein) is in the form of a concentrate whichmay be combined with additional oil to form, in whole or in part, afinished lubricant), the ratio of these additives to the oil oflubricating viscosity and/or to diluent oil include the ranges of 1:99to 99:1 by weight, or 80:20 to 10:90 by weight. If the lubricatingcomposition (comprising the additives disclosed herein) is in the formof a finished lubricant, the ratio of these additives to the oil oflubricating viscosity and/or to diluent oil include the ranges of 1:99.9to 50:50 by weight, or 1:99 to 30:70 by weight.

Additional Performance Additives

The lubricating composition optionally includes one or more additionalperformance additives. These additional performance additives mayinclude one or more metal deactivators, viscosity modifiers, detergents,friction modifiers, antiwear agents, corrosion inhibitors, dispersants,dispersant viscosity modifiers (other than the exemplary compound),extreme pressure agents, antioxidants, foam inhibitors, demulsifiers,pour point depressants, seal swelling agents, antiwear agents, and anycombination or mixture thereof. Typically, fully-formulated lubricatingoil will contain one or more of these performance additives, and often apackage of multiple performance additives.

In one embodiment, the lubricating composition further includes adispersant, an antiwear agent, a friction modifier, a viscositymodifier, an antioxidant, an overbased detergent, or a combinationthereof, where each of the additives listed may be a mixture of two ormore of that type of additive. In one embodiment, the lubricatingcomposition further includes a polyisobutylene succinimide dispersant,an antiwear agent, a friction modifier, a viscosity modifier (typicallyan olefin copolymer such as an ethylene-propylene copolymer), anantioxidant (including phenolic and aminic antioxidants), an overbaseddetergent (including overbased sulfonates and phenates), or acombination thereof, where each of the additives listed may be a mixtureof two or more of that type of additive.

In one embodiment, the lubricating composition further includes anantiwear agent such as a metal dihydrocarbyl dithiophosphate (typicallyzinc dialkyldithiophosphate), wherein the metal dihydrocarbyldithiophosphate contributes at least 100 ppm, or at least 200 ppm, or200 ppm to 1000 ppm, or 300 ppm to 800 ppm, or 400 ppm to 600 ppm ofphosphorus to the lubricating composition. In one embodiment, thelubricating composition is free of or substantially free of zincdialkyldithiophosphate (ZDDP).

In one embodiment, the lubricating composition further includes adispersant (other than the exemplary dispersant viscosity modifier). Thedispersant may be present at a concentration of 0 wt % to 20 wt %, suchas at least 0.01 wt %, or at least 0.1 wt %, or at least 0.1 wt %, or atleast 1 wt %, or up to 20 wt %, or up to 15 wt %, or up to 10 wt %, orup to 6 wt % of the lubricating composition. In one embodiment, thedispersant may be present in the composition at a concentration of 0.2wt % to 2 wt %.

Suitable dispersants for use in the exemplary lubricating compositionsinclude succinimide dispersants. In one embodiment, the dispersant maybe present as a single dispersant. In one embodiment, the dispersant maybe present as a mixture of two or three different dispersants, whereinat least one may be a succinimide dispersant.

The succinimide dispersant may be a derivative of an aliphaticpolyamine, or mixtures thereof. The aliphatic polyamine may be aliphaticpolyamine such as an ethylenepolyamine, a propylenepolyamine, abutylenepolyamine, or mixtures thereof. In one embodiment, the aliphaticpolyamine may be ethylenepolyamine. In one embodiment, the aliphaticpolyamine may be selected from the group consisting of ethylenediamine,diethylenetriamine, triethylenetetramine, tetraethylenepentamine,pentaethylenehexamine, polyamine still bottoms, and mixtures thereof.

The dispersant may be a N-substituted long chain alkenyl succinimide.Examples of N-substituted long chain alkenyl succinimides includepolyisobutylene succinimide. Typically, the polyisobutylene from which apolyisobutylene succinic anhydride is derived has a number averagemolecular weight of 350 to 5000, or 550 to 3000 or 750 to 2500.Succinimide dispersants and their preparation are disclosed, forexample, in U.S. Pat. Nos. 3,172,892, 3,219,666, 3,316,177, 3,340,281,3,351,552, 3,381,022, 3,433,744, 3,444,170, 3,467,668, 3,501,405,3,542,680, 3,576,743, 3,632,511, 4,234,435, Re 26,433, and U.S. Pat.Nos. 6,165,235, 7,238,650, and EP Patent Application 0 355 895 A.

The dispersant may also be post-treated by conventional methods by areaction with any of a variety of agents. Among these are boroncompounds, urea, thiourea, dimercaptothiadiazoles, carbon disulfide,aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinicanhydrides, maleic anhydride, nitriles, epoxides, and phosphoruscompounds.

In one embodiment, the lubricating composition further includes adispersant viscosity modifier other than the aminated dispersantviscosity modifier described herein. The additional dispersant viscositymodifier may be present at a concentration of 0 wt % to 5 wt %, such asat least 0.01 wt %, or at least 0.05 wt %, or up to 5 wt %, or up to 4wt %, or up to 2 wt % of the lubricating composition.

Suitable dispersant viscosity modifiers include functionalizedpolyolefins, for example, ethylene-propylene copolymers that have beenfunctionalized with an acylating agent such as maleic anhydride and anamine; polymethacrylates functionalized with an amine, and esterifiedstyrene-maleic anhydride copolymers reacted with an amine. Exemplarydispersant viscosity modifiers are disclosed, for example, inWO2006/015130 and U.S. Pat. Nos. 4,863,623; 6,107,257; 6,107,258; and6,117,825.

In one embodiment, the lubricating composition further includes aphosphorus-containing antiwear agent. The antiwear agent may be presentat a concentration of 0 wt % to 3 wt %, such as at least 0.1 wt %, or atleast 0.5 wt %, or up to 3 wt %, or up to 1.5 wt %, or up to 0.9 wt % ofthe lubricating composition. The phosphorus-containing antiwear agentmay be a zinc dialkyldithiophosphate, or mixture thereof.

In one embodiment, the lubricating composition further includes amolybdenum compound. The molybdenum compound may provide the lubricatingcomposition with 0 to 1000 ppm, or 5 to 1000 ppm, or 10 to 750 ppm 5 ppmto 300 ppm, or 20 ppm to 250 ppm of molybdenum. The molybdenum compoundmay be selected from the group consisting of molybdenumdialkyldithiophosphates, molybdenum dithiocarbamates, amine salts ofmolybdenum compounds, and mixtures thereof.

In one embodiment, the lubricating composition further includes anoverbased detergent. The overbased detergent may be present at 0 wt % to15 wt %, or at least 0.1 wt %, or at least 0.2 wt %, or at least 0.2 wt%, or up to 15 wt %, or up to 10 wt %, or up to 8 wt %, or up to 3 wt %of the lubricating composition. For example, in a heavy duty dieselengine, the detergent may be present at 2 wt % to 3 wt % of thelubricating composition. For a passenger car engine, the detergent maybe present at 0.2 wt % to 1 wt % of the lubricating composition.

The overbased detergent may be selected from the group consisting ofnon-sulfur containing phenates, sulfur containing phenates, sulfonates,salixarates, salicylates, and mixtures thereof.

The overbased detergent may also include “hybrid” detergents formed withmixed surfactant systems including phenate and/or sulfonate components,e.g., phenate/salicylates, sulfonate/phenates, sulfonate/salicylates,sulfonates/phenates/salicylates, as described; for example, in U.S. Pat.Nos. 6,429,178; 6,429,179; 6,153,565; and 6,281,179. Where, for example,a hybrid sulfonate/phenate detergent is employed, the hybrid detergentcan be considered equivalent to amounts of distinct phenate andsulfonate detergents introducing like amounts of phenate and sulfonatesoaps, respectively.

Suitable overbased detergents are sodium salts, calcium salts, magnesiumsalts, or mixtures of the phenates, sulfur containing phenates,sulfonates, salixarates and salicylates. Overbased phenates andsalicylates may have a total base number of 180 to 450 TBN. Overbasedsulfonates may have a total base number of 250 to 600, or 300 to 500. Inone embodiment, the sulfonate detergent may be predominantly a linearalkylbenzene sulfonate detergent having a metal ratio of at least 8, asdescribed, for example, in U.S. Pub. No. 20050065045. The linearalkylbenzene sulfonate detergent may be particularly useful forassisting in improving fuel economy. The linear alkyl group may beattached to the benzene ring anywhere along the linear chain of thealkyl group, but often in the 2, 3, or 4 position of the linear chain,and in some instances, predominantly in the 2 position, resulting in thelinear alkylbenzene sulfonate detergent.

In one embodiment, the lubricating composition includes an antioxidant,or mixture of antioxidants. The antioxidant may be present at 0 wt % to15 wt 5, or 0.1 wt % to 10 wt %, or 0.5 wt % to 5 wt % of thelubricating composition.

Antioxidants include sulfurized olefins, alkylated diarylamines(typically alkylated phenyl naphthyl amines for example thosecommercially available as Irganox® L 06 from CIBA, or alkylateddiphenylamines such as dinonyl diphenylamine, octyl diphenylamine,dioctyl diphenylamine), hindered phenols, molybdenum compounds (such asmolybdenum dithiocarbamates), or mixtures thereof.

The hindered phenol antioxidant often contains a secondary butyl and/ora tertiary butyl group as a sterically hindering group. The phenol groupmay be further substituted with a hydrocarbyl group (typically linear orbranched alkyl) and/or a bridging group linking to a second aromaticgroup. Examples of suitable hindered phenol antioxidants include2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol,4-ethyl-2,6-di-tert-butylphenol, 4-propyl-2,6-di-tert-butylphenol or4-butyl-2,6-di-tert-butylphenol, or 4-dodecyl-2,6-di-tert-butylphenol.In one embodiment, the hindered phenol antioxidant may be an ester andmay include, e.g., Irganox™ L-135 from Ciba. A more detailed descriptionof suitable ester-containing hindered phenol antioxidant chemistry isfound in U.S. Pat. No. 6,559,105.

In one embodiment, the lubricating composition further includes afriction modifier. The friction modifier may be present at 0 wt % to 6wt %, such as at least 0.05 wt %, or at least 0.1 wt %, or up to 6 wt %,or up to 4 wt %, or up to 2 wt % of the lubricating composition. In oneembodiment, the friction modifier is present in the composition at 0.1to 1.0 wt %. Examples of friction modifiers include long chain fattyacid derivatives of amines, fatty esters, or epoxides; fattyimidazolines such as condensation products of carboxylic acids andpolyalkylene-polyamines; amine salts of alkylphosphoric acids; fattyalkyl tartrates; fatty alkyl tartrimides; or fatty alkyl tartramides. Insome embodiments, the term fatty, as used herein, can mean having a C₈to C₂₂ linear alkyl group.

Friction modifiers may also encompass materials such as sulfurized fattycompounds and olefins, molybdenum dialkyldithiophosphates, molybdenumdithiocarbamates, sunflower oil or monoester of a polyol and analiphatic carboxylic acid.

In one embodiment, the friction modifier may be selected from the groupconsisting of long chain fatty acid derivatives of amines, long chainfatty esters, or long chain fatty epoxides; fatty imidazolines; aminesalts of alkylphosphoric acids; fatty alkyl tartrates; fatty alkyltartrimides; and fatty alkyl tartramides.

In one embodiment, the friction modifier may be a long chain fatty acidester. In another embodiment, the long chain fatty acid ester may be amonoester or a diester or a mixture thereof, and in another embodimentthe long chain fatty acid ester may be a triglyceride.

Other performance additives such as corrosion inhibitors include thosedescribed in U.S. Pub. No. 20050038319, octyl octanamide, condensationproducts of dodecenyl succinic acid or anhydride and a fatty acid suchas oleic acid with a polyamine. In one embodiment, the corrosioninhibitors include a Synalox® corrosion inhibitor. The Synalox®corrosion inhibitor may be a homopolymer or copolymer of propyleneoxide. Synalox® corrosion inhibitors are described in a productbrochure, Form No. 118-01453-0702 AMS, entitled “SYNALOX Lubricants,High-Performance Polyglycols for Demanding Applications,” published byThe Dow Chemical Company.

Metal deactivators including derivatives of benzotriazoles (such astolyltriazole), dimercaptothiadiazole derivatives, 1,2,4-triazoles,benzimidazoles, 2-alkyldithiobenzimidazoles, or2-alkyldithiobenzothiazoles; foam inhibitors including copolymers ofethyl acrylate and 2-ethylhexylacrylate and copolymers of ethyl acrylateand 2-ethylhexylacrylate and vinyl acetate; demulsifiers includingtrialkyl phosphates, polyethylene glycols, polyethylene oxides,polypropylene oxides and (ethylene oxide-propylene oxide) polymers; pourpoint depressants including esters of maleic anhydride-styrene,polymethacrylates, polyacrylates or polyacrylamides may be useful.

Pour point depressants that may be useful in the compositions of theinvention include polyalphaolefins, esters of maleic anhydride-styrene,poly(meth)acrylates, polyacrylates or polyacrylamides.

In different embodiments, the lubricating composition may have acomposition as described in Table 1:

TABLE 1 Example Lubricating Compositions Embodiments (wt %) Additive A BC Exemplary Aminated Dispersant 0.05 to 10 0.2 to 3 0.5 to 2 ViscosityModifier Dispersant 0.05 to 12 0.75 to 8 0.5 to 6 Overbased Detergent 0or 0.05 to 15 0.1 to 10 0.2 to 8 Antioxidant 0 or 0.05 to 15 0.1 to 100.5 to 5 Antiwear Agent 0 or 0.05 to 15 0.1 to 10 0.3 to 5 FrictionModifier 0 or 0.05 to 6 0.05 to 4 0.1 to 2 Viscosity Modifier 0 or 0.05to 10 0.5 to 8 1 to 6 Any Other Performance Additive 0 or 0.05 to 10 0or 0.05 to 8 0 or 0.05 to 6 Oil of Lubricating Viscosity Balance to 100Balance to 100 Balance to 100

The aminated dispersant viscosity modifier may be present in embodiments(D) at 0.1 to 8 wt %, or (E) 1 to 7 wt %, or (F) 2 to 6 wt %, or (G) 0.1to 2 wt %, or (H) 0.3 to 1.2 wt % of the lubricating composition, withthe amount of dispersant, overbased detergent, antioxidant, antiwearagent, friction modifier, viscosity modifier, any other performanceadditive and an oil of lubricating viscosity in amounts shown in thetable above for embodiments (A) to (C).

INDUSTRIAL APPLICATIONS

In one embodiment, a method of lubricating an internal combustion engineincludes supplying to the internal combustion engine a lubricatingcomposition as disclosed herein. Generally, the lubricating compositionis added to the lubricating system of the internal combustion engine,which then delivers the lubricating composition to the critical parts ofthe engine, during its operation, that require lubrication.

In one embodiment, a use of the dispersant viscosity modifier describedherein to improve film thickness and/or antiwear performance of alubricating composition is provided. These improvements can beconsidered in addition to the dispersancy and viscosity controlperformance expected from a dispersant viscosity modifier.

The lubricating compositions described above may be utilized in aninternal combustion engine. The engine components may have a surface ofsteel or aluminum (typically a surface of steel), and may also be coatedfor example, with a diamond like carbon (DLC) coating. An aluminumsurface may comprise an aluminum alloy that may be a eutectic orhyper-eutectic aluminum alloy (such as those derived from aluminumsilicates, aluminum oxides, or other ceramic materials). The aluminumsurface may be present on a cylinder bore, cylinder block, or pistonring formed of an aluminum alloy or aluminum composite.

The internal combustion engine may or may not have an Exhaust GasRecirculation system. The internal combustion engine may be fitted withan emission control system or a turbocharger. Examples of the emissioncontrol system include diesel particulate filters (DPF), or systemsemploying selective catalytic reduction (SCR).

In one embodiment, the internal combustion engine may be a diesel fueledengine (such as a heavy duty diesel engine), a gasoline fueled engine, anatural gas fueled engine or a mixed gasoline/alcohol fueled engine. Inone embodiment, the internal combustion engine may be a diesel fueledengine and in another embodiment a gasoline fueled engine. In oneembodiment, the internal combustion engine may be a biodiesel fueledengine. The internal combustion engine may be a 2-stroke or 4-strokeengine. Suitable internal combustion engines include marine dieselengines, aviation piston engines, low-load diesel engines, andautomobile and truck engines. In one embodiment the internal combustionengine is a gasoline direct injection (GDI) engine.

The internal combustion engine is distinct from gas turbine. In aninternal combustion engine, individual combustion events which throughthe rod and crankshaft translate from a linear reciprocating force intoa rotational torque. In contrast, in a gas turbine (which may also bereferred to as a jet engine) it is a continuous combustion process thatgenerates a rotational torque continuously without translation and canalso develop thrust at the exhaust outlet. These differences result inthe operation conditions of a gas turbine and internal combustion enginedifferent operating environments and stresses.

The lubricating composition for an internal combustion engine may besuitable for use as an engine lubricant irrespective of the sulfur,phosphorus or sulfated ash (ASTM D-874) content. The sulfur content ofthe lubricating composition, which is particularly suited to use as anengine oil lubricant, may be 1 wt % or less, or 0.8 wt % or less, or 0.5wt % or less, or 0.3 wt % or less. In one embodiment, the sulfur contentmay be in the range of 0 wt % to 0.5 wt %, or 0.01 wt % to 0.3 wt %. Thephosphorus content may be 0.2 wt % or less, or 0.12 wt % or less, or 0.1wt % or less, or 0.085 wt % or less, or 0.08 wt % or less, or even 0.06wt % or less, 0.055 wt % or less, or 0.05 wt % or less. In oneembodiment, the phosphorus content may be 100 ppm to 1000 ppm, or 200ppm to 600 ppm. The total sulfated ash content may be 2 wt % or less, or1.5 wt % or less, or 1.1 wt % or less, or 1 wt % or less, or 0.8 wt % orless, or 0.5 wt % or less, or 0.4 wt % or less. In one embodiment, thesulfated ash content may be 0.05 wt % to 0.9 wt %, or 0.1 wt % to 0.2 wt% or to 0.45 wt %. In one embodiment, the lubricating composition may bean engine oil, wherein the lubricating composition may be characterizedas having at least one of (i) a sulfur content of 0.5 wt % or less, (ii)a phosphorus content of 0.1 wt % or less, (iii) a sulfated ash contentof 1.5 wt % or less, or combinations thereof.

EXAMPLES

The invention will be further illustrated by the following examples,which set forth particularly advantageous embodiments. While theexamples are provided to illustrate the invention, they are not intendedto limit it.

As used herein kinematic viscosity is measured at 100° C. (KV₁₀₀),according to the method of ASTM D445-12, “Standard Test Method forKinematic Viscosity of Transparent and Opaque Liquids (and Calculationof Dynamic Viscosity)”, ASTM International, West Conshohocken, Pa., DOI:10.1520/D0445-12. This test method specifies a procedure for thedetermination of the kinematic viscosity, of liquid petroleum productsby measuring the time for a volume of liquid to flow under gravitythrough a calibrated glass capillary viscometer. It may be noted that 1mm²/s=10⁻⁶ m²/s=1 cSt.

The viscosity index (VI) is determined according to ASTM D2270-10e1,“Standard Practice for Calculating Viscosity Index From KinematicViscosity at 40 and 100° C.,” DOI: 10.1520/D2270-10E01.

The High Temperature/High Shear rate, HTHS (150° C.), of a lubricatingcomposition containing the exemplary dispersant viscosity modifier isdetermined according to the procedure defined in ASTM D 4683-10,“Standard Test Method for Measuring Viscosity of New and Used EngineOils at High Shear Rate and High Temperature by Tapered BearingSimulator Viscometer at 150° C.,” ASTM International, West Conshohocken,Pa., which is also known as the Mini Rotary Viscometer test (MRV). Thistest method determines the viscosity of an oil at 150° C. and 1.0·10⁶s⁻¹ using a viscometer having a slightly tapered rotor and stator calledthe Tapered Bearing Simulator (TBS) Viscometer. Unless otherwise noted,HTHS values are determined by this method and are reported in centipoise(cP). 1 centipoise=1 mPa−second.

Low temperature flow to an engine oil pump or oil distribution system issimulated by cold crank measurements in centipoise according to ASTMD5293-14, “Standard Test Method for Apparent Viscosity of Engine Oilsand Base Stocks Between −5° C. and −35° C. Using Cold-CrankingSimulator,” DOI: 10.1520/D5293-14.

Example 1: Preparation of a 3.5% Maleated Ethylene Propylene AminoethylEthylene Urea Dispersant Viscosity Modifier

A maleated aminoethyl ethylene urea dispersant viscosity modifier isprepared from aminoethyl ethylene urea and a maleated ethylene propylenecopolymer, commercially available from Mitusi as Lucant™ A-5320H.

A 3-L, four-neck flask equipped with a mechanical stirrer, a thermowell,sub-surface nitrogen inlet, and Dean-Stark trap with condenser ischarged with Lucant A-5320H (900.0 g) and diluent oil (936.2 g) andheated to 100° C. Aminoethylethylene urea (42.1 g) is charged to theflask and the flask contents heated to 160° C. Once at temperature thecontents are stirred for 3 h. Upon filtration the product (1798.3 g) isobtained as a viscous oil. The resulting dispersant viscosity modifieris referred to below as 3.5% MAA urea.

Example 2: Preparation of a 3.5% Maleated Ethylene PropyleneAminopropanol Dispersant Viscosity Modifier

A 5-L, 4-neck flask equipped with a mechanical stirrer, thermowell,sub-surface nitrogen inlet, and Dean-Stark trap with condenser ischarged with Lucant A-5320H (1600.0 g) and 3-aminopropanol (87.0 g). Thecontents of the flask are stirred and heated to 150° C. At around 100°C., the contents form a gel and stirring is halted. Heating is continuedand the gel breaks up around 140° C. Stirring is then resumed. With theflask contents at 150° C., additional Lucant A-5320H (1600.0 g) is addedto the flask over the course of 8 hours. After complete addition, theflask is held at 150° C. for 2 hours. The flask temperature is thenincreased to 160° C. and held for 6 hours. A second charge of3-aminopropanol (4.8 g) is added to the flask and the temperature heldat 160° C. for an additional 5.5 hours. With the flask at 160° C.,vacuum is applied to less than 1 mmHg (133 Pascal) and held for 1 hour.The vacuum is then released and flask contents cooled, providing theproduct (3179.2 g) as a viscous oil. The resulting dispersant viscositymodifier is referred to below as 3.5% MAA aminopropanol.

Example 3: Preparation of a 6.5% Maleated Ethylene Propylene Copolymer

A 2-L, 4-neck flask equipped with a mechanical stirrer, thermowell,sub-surface nitrogen inlet, and an air condenser with attached watercooled condenser is charged with Lucant HC-2000 (1000.0 g), acommercially available olefin copolymer supplied by Mitsui. The contentsof the flask are heated to 160° C. with a sub-surface nitrogen purge of0.5 SCFH for 1 hour. Di-tert-butylperoxide (16.0 g) and maleic anhydride(76.0 g) are charged simultaneously to the flask over the course of 2.75hours. The contents of the flask are held at 160° C. for 0.75 hours,then the temperature increased to 180° C. with vacuum being applied to20 mmHg (2666 Pa) for 4 hours. The vacuum is then released and uponcooling, the product is obtained as a viscous oil (1024.6 g).

Example 4: Preparation of a 6.5% Maleated Ethylene PropyleneAminopropanol Dispersant Viscosity Modifier

A 3-L, 4-neck flask equipped with a mechanical stirrer, thermowell,sub-surface nitrogen inlet, and Dean-Stark trap with condenser ischarged with the 6.5 wt % maleated ethylene propylene copolymer fromExample 3 (550.0 g) and diluent oil (1213.2 g) and stirred untilhomogenous. 869.2 g of this polymer solution is transferred to anaddition funnel; the rest of the solution remains in the flask.3-Aminopropanol (30.3 g) is charged to the flask and the contents of theflask are stirred and heated to 150° C. At approximately 100° C., theflask contents begin to gel and stirring is halted. Near 140° C., thegel breaks and stirring is restarted. When the flask temperature reaches150° C., the polymer solution in the addition funnel is charged to theflask over 5 hours, after which the flask is held at 150° C. for 5hours. Vacuum is applied to the flask at 4 mmHg (533 Pa) for 30 min. Thevacuum is then released and the product is filtered, providing theproduct as an orange viscous oil (1712.0 g). The resulting dispersantviscosity modifier is referred to below as 6.5% MAA aminopropanol.

Preparation of Lubricating Compositions

1. Passenger Car Engine Oil Formulation

The dispersant viscosity modifier of Example 1 is prepared at 50 wt %polymer in 50 wt % diluent oil. The dispersant viscosity modifier ofExample 2 is prepared at 100 wt % polymer in 0 wt % diluent oil.

This is blended into a group III base oil in amounts by weight to formlubricating compositions, as summarized in Table 2 below. ComparativeExample 5 includes an amine-free dispersant viscosity modifier (apolymethacrylate (84% C12-15 methacrylate/16% methyl methacrylate), witha weight average molecular weight of 330,000). Examples 6 and 7 containthe dispersant viscosity modifiers of Examples 1 and 2 respectively aswell as some of the amine-free dispersant viscosity modifier used inExample 5.

Each of the blends is designed to have nearly equivalent kinematicviscosities at 100° C. (KV₁₀₀) to allow for direct comparison:

KV₁₀₀ about 8.65 cSt, VI about 235, HTHS (150° C.) about 2.6 cP, D5293(−35) cold crank about 3650 cP.

TABLE 2 Treat rates (wt % of Lubricating Composition) Lubricatingcomposition Comparative Ex. 5 Ex. 6 Ex 7 3.5% MAA urea from Ex. 1 0.72(0.36) 3.5% MAA 3-aminopropanol 0.36 from Ex. 2 (0.36) amine-freedispersant viscosity 6.01 5.01 5.01 modifier (2.16) (1.80) (1.80) PourPoint Depressant 0.1 0.1 0.1 Dispersant-Inhibitor Package 9.18 9.18 9.18Base Oil balance balance balance

The data in parenthesis is the amount of actives for each component. Theweight % actives are based on the entire composition. TheDispersant-Inhibitor Package may include some oil. The lubricatingcompositions of Examples 5-7 include about 0.75% zincdialkyldithiophosphate (ZDDP) (which delivers about 0.076% phosphorus tothe lubricating composition).

Friction properties were determined using a Mini Traction Machine (MTM).The lubricants are evaluated in a commercially-available mini-tractiontester machine. A simulated concentrated contact forms between a steelball and a steel disc (Smooth disk). Traction measurements are made at arolling speed (of the steel ball) of 2.5 m/s and a 20% slide to rollratio. The temperature was 140° C. and load was 72N. FIG. 1 shows theStribeck curve obtained.

Given the parameters of this particular experiment the performance ofboth the 3.5% MAA urea and the 3.5% MAA aminopropanol in the finishedfluid can be measured in all three regions of the Stribeck curve. Thearea of interest is the mixed regime, which can be found between the twovertical lines. The mixed regime is indicative of the durability of thefriction modifier characteristics of the dispersant viscosity modifier,as determined by the Sequence VID engine test (ASTM D7589), which isheavily weighted towards the mixed regime.

From the MTM data, both the 3.5% MAA urea and the 3.5% MAA aminopropanoloutperformed the baseline formulation (Ex. 5).

2. Heavy Duty Engine Oil Formulation

For this study, comparative Example 8 includes the dispersant viscositymodifier of Example 3 (32 wt % polymer, 68 wt % oil). In the blend ofExample 9, this is replaced with the 6.5% MAA aminopropanol of Example 4(prepared at 32 wt % polymer, 68 wt % oil) at a treat rate to obtain thefollowing viscometric parameters:

Kv₁₀₀ about 12-10.5 cSt HTHS (150° C.) ≥3.5 cP D5293 (−25) cold crankabout 5800-6600 cP

The treat rate for the 6.5% MAA aminopropanol and Baseline (Ex. 8) canbe found in Table 3.

TABLE 3 Treat rates (wt % of Lubricating Composition) Comp. Ex. 8 Ex. 9dispersant viscosity modifier from 2.05 (0.66 Ex. 3, wt % wt % active)6.5% MAA 3-aminopropanol from 2.20 (0.7 Ex 4, wt % wt % active)Viscosity Modifier 3.9 (0.49 3.9 (0.49 wt % active) wt % active) PourPoint Depressant 0.2 0.2 Dispersant-Inhibitor Package 14.85 14.85 BaseOil Balance Balance

The weight % actives are also based on the entire composition. Thelubricating compositions of Examples 8 and 9 include about 1% zincdialkyldithiophosphate (ZDDP) (which delivers about 0.11% phosphorus tothe composition). The compositions include about 1% sulfated ash andhave a TBN of about 8.5.

The film thickness of the blends in Table 3 when subjected to boundary,mixed and hydrodynamic lubrication conditions is measured by anelastohydrodynamic (EHD) ball on plate rig. Briefly, a chamber isflooded with one of the blends from Table 3. The chamber is equippedwith a ball that rolls on a glass plate and a chromium spacer. Bydigital analysis of the interference patter of reflected light shined onthe ball in contact with the plate, the film thickness is measured tothe nanometer scale. The experiment is performed at 140° C. over avariety of rolling speeds. Conditions are as follows: 0.5 GPa HertzPressure, 17 N.

FIG. 2 shows the EHD data obtained. It can be seen that the Example 9dispersant viscosity modifier forms a thicker film, as compared tocomparative Example 8.

The term “hydrocarbyl group” is used herein in its ordinary sense, whichis well-known to those skilled in the art. Specifically, it refers to agroup having a carbon atom directly attached to the remainder of themolecule and having predominantly hydrocarbon character. Examples ofhydrocarbyl groups include:

(i) hydrocarbon substituents, that is, aliphatic (e.g., alkyl oralkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, andaromatic-, aliphatic-, and alicyclic-substituted aromatic substituents,as well as cyclic substituents wherein the ring is completed throughanother portion of the molecule (e.g., two substituents together form aring);

(ii) substituted hydrocarbon substituents, that is, substituentscontaining non-hydrocarbon groups which, in the context of thisinvention, do not alter the predominantly hydrocarbon nature of thesubstituent (e.g., halo (especially chloro and fluoro), hydroxy, alkoxy,mercapto, alkylmercapto, nitro, nitroso, and sulfoxy);

(iii) hetero substituents, that is, substituents which, while having apredominantly hydrocarbon character, in the context of this invention,contain other than carbon in a ring or chain otherwise composed ofcarbon atoms.

Heteroatoms include sulfur, oxygen, nitrogen, and encompass substituentssuch as pyridyl, furyl, thienyl, and imidazolyl. In general, no morethan two, and in some embodiments, no more than one non-hydrocarbonsubstituent is present for every ten carbon atoms in the hydrocarbylgroup. In one embodiment, there are no non-hydrocarbon substituents inthe hydrocarbyl group.

It is known that some of the materials described above may interact inthe final formulation, so that the components of the final formulationmay be different from those that are initially added. The productsformed thereby, including the products formed upon employing lubricantcomposition of the present invention in its intended use, may not besusceptible of easy description. Nevertheless, all such modificationsand reaction products are included within the scope of the presentinvention; the present invention encompasses lubricant compositionprepared by admixing the components described above.

Each of the documents referred to above is incorporated herein byreference in its entirety, as is the priority document and all relatedapplications, if any, of which this application claims the benefit.Except in the Examples, or where otherwise explicitly indicated, allnumerical quantities in this description specifying amounts ofmaterials, reaction conditions, molecular weights, number of carbonatoms, and the like, are to be understood as modified by the word“about.” Unless otherwise indicated, each chemical or compositionreferred to herein should be interpreted as being a commercial gradematerial which may contain the isomers, by-products, derivatives, andother such materials which are normally understood to be present in thecommercial grade. However, the amount of each chemical component ispresented exclusive of any solvent or diluent oil, which may becustomarily present in the commercial material, unless otherwiseindicated. It is to be understood that the upper and lower amount,range, and ratio limits set forth herein may be independently combined.Similarly, the ranges and amounts for each element of the invention maybe used together with ranges or amounts for any of the other elements.

While the invention has been explained in relation to its preferredembodiments, it is to be understood that various modifications thereofwill become apparent to those skilled in the art upon reading thespecification. Therefore, it is to be understood that the inventiondisclosed herein is intended to cover such modifications as fall withinthe scope of the appended claims.

1. A lubricating composition comprising: an oil of lubricatingviscosity; and an oil-soluble dispersant viscosity modifier comprising:an olefin-based polymer backbone, and at least one pendent group derivedfrom a functionalized aliphatic amine, the functionalized aliphaticamine comprising an alkanolamine having the formula:

where R¹ is an alkyl group having from 1 to 20 carbon atoms, each of theat least one pendent groups being independently attached to theolefin-based polymer backbone and being non-ionic, non-basic, andnon-acidic. 2-7. (canceled)
 8. The lubricating composition of claim 1,wherein the functionalized aliphatic amine is selected from the groupconsisting of ethanolamine, 3-aminopropan-1-ol, 4-aminobutan-1-ol,5-aminopentan-1-ol, 6-aminohexan-1-ol, 7-aminoheptan-1-ol,8-aminooctan-1-ol, 2-(2-aminoethylamino)ethanol,3-amino-2,2-dimethylpropan-1-ol, 2-(2-aminoethoxy)ethanol,N-(2-hydroxyethyl)-1,3-propanediamine, and mixtures thereof. 9-15.(canceled)
 16. The lubricating composition of claim 1, wherein thefunctional group is spaced from a nitrogen derived from thefunctionalized aliphatic amine by a C₄-C₂₄ hydrocarbyl group.
 17. Thelubricating composition of claim 1, wherein the olefin-based polymerbackbone comprises units derived from (i) an α-olefin monomer and (ii)an ethylenically unsaturated carboxylic acid monomer or derivativethereof.
 18. The lubricating composition of claim 17, wherein theethylenically unsaturated carboxylic acid monomer is selected from thegroup consisting of maleic anhydride, maleic anhydrides, chlormaleicanhydride, itaconic anhydride, and corresponding dicarboxylic acids andesters thereof, alkyl-substituted derivatives thereof, and mixturesthereof.
 19. (canceled)
 20. (canceled)
 21. The lubricating compositionof claim 1, wherein a ratio by weight of the pendent groups to thepolymer backbone in the dispersant viscosity modifier is up to 10:100.22. The lubricating composition of claim 1, wherein the dispersantviscosity modifier comprises at least two of the pendent groups permolecule of the dispersant viscosity modifier, on average.
 23. Thelubricating composition of claim 1, wherein the dispersant viscositymodifier has: an HLB value of at least 2 and up to 6, where HLB=20*Mh/M,where Mh is the molecular mass of the hydrophilic portion of themolecule and M is the molecular mass of the whole molecule; a TBN of upto 5, on an oil-free basis, according to the method described in ASTMD2896-11; and a TAN of up to 5, on an oil-free basis, according to themethod described in ASTM D664-11A. 24-26. (canceled)
 27. The lubricatingcomposition of claim 1, wherein the olefin-based polymer backbonecomprises an ethylene-olefin-based copolymer.
 28. The lubricatingcomposition of claim 27, wherein ethylene-olefin-based copolymercomprises at least 10 mole percent ethylene.
 29. The lubricatingcomposition of claim 1, wherein the olefin-based polymer backbone has anumber average molecular weight greater of at least
 1000. 30. Thelubricating composition of claim 1, wherein the oil of lubricatingviscosity is present in the composition at a concentration of at least10 wt. %.
 31. The lubricating composition of claim 1, wherein thedispersant viscosity modifier is present in the composition at aconcentration of at least 0.05 wt. %.
 32. The lubricating composition ofclaim 1, wherein the oil of lubricating viscosity has a kinematicviscosity at 100° C., as determined by ASTM D445-12, of less than 15mm²/s or at least 35 mm²/s.
 33. (canceled)
 34. The lubricatingcomposition of claim 1, wherein the composition further comprises atleast one of a dispersant, a detergent, an overbased detergent, anantioxidant a viscosity modifier, a friction modifier, a corrosioninhibitor, a pour point depressant, a seal swell agent, a demulsifier,and an antiwear agent.
 35. (canceled)
 36. A process for making alubricating composition comprising: (i) providing an ethylene propylenebased polymer backbone comprising acylating groups derived from maleicanhydride; (ii) reacting at least one of the acylating groups with afunctionalized aliphatic amine to provide an aminated dispersantviscosity modifier with at least one pendent group, each of the at leastone pendent group being independently attached to the olefin-basedpolymer backbone, each of the at least one pendent group beingnon-ionic, non-basic, and non-acidic, the functionalized aliphatic aminecomprising 3-aminopropanol or aminoethyl ethylene urea; and (iii)combining the aminated dispersant viscosity modifier with an oil oflubricating viscosity, and at least one performance additive to providea lubricating composition with a sulfur content of 0.5 wt. % or less, aphosphorus content of 0.1 wt. % or less, and a sulfated ash content of1.5 wt. % or less.
 37. The process of claim 36, wherein the providing ofthe olefin-based polymer with one or more acylating linking groupscomprises grafting one or more unsaturated carboxylic reactants onto anolefin-based polymer backbone.
 38. The lubricating composition of claim1, wherein the lubricating composition has a sulfur content of 0.5 wt. %or less, a phosphorus content of 0.1 wt. % or less, and a sulfated ashcontent of 1.5 wt. % or less.
 39. A method for lubricating an internalcombustion engine comprising: supplying to the internal combustionengine the lubricating composition of claim
 1. 40. A lubricatingcomposition comprising: an oil of lubricating viscosity; and anoil-soluble dispersant viscosity modifier comprising: anethylene-olefin-based polymer backbone, and at least one pendent groupderived from a functionalized aliphatic amine, the at least one pendentgroup being selected from: